However, in the Unicode Standard, Zyyy marks characters that are common across
a number of scripts (like 1,2,3, . ; ? and so on). Because of that, in a Unicode context it
is viewed as being more like "in multiple scripts", and not really appropriate for locales.

Zzzz marks reserved characters which may end up becoming any script once encoded (see
Values in UTR#24). It is also the
value used for Unknown script in CLDR. In practice, it is rare to know the language without
the script (en-Zzzz would be an odd case, for example), so this is used mostly for API
return values.

A. Many LDML elements are display names. Display names describe languages,
scripts, countries, variants, units, and many other items. It is a translated
name for use in user-interfaces for displaying lists. The translator should
adopt the capitalization rules for menu lists, appropriate for the target language.

Currencies may also have a display name. With the introduction of pluralized
units, it is recognized that currencies may also be used in user-interfaces with flowing text.
For currency names, the translator may adopt a capitalization rule suitable for use in both menu
lists and flowing text, although we recognize, there may be limitations with this strategy,
at this time.